package com.awangyh.net.nio;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.time.LocalDateTime;
import java.util.Iterator;
import java.util.Set;

/**
 * @author: wangyanhui
 * @since: 2017/4/28
 */
public class MultipleexerTimeServer implements Runnable {

    private Selector selector;

    private ServerSocketChannel serverSocketChannel;

    private volatile boolean stop;

    public MultipleexerTimeServer(int port) {
        try {
            selector = Selector.open();
            serverSocketChannel = ServerSocketChannel.open();
            serverSocketChannel.configureBlocking(false);
            serverSocketChannel.socket().bind(new InetSocketAddress(port),1024);
            serverSocketChannel.register(selector, SelectionKey.OP_ACCEPT);

            System.out.println("The time server is start in port: " + port);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void stop() {
        this.stop = true;
    }

    @Override
    public void run() {
        while ( !stop) {
            try {
                selector.select(1000);
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                Iterator<SelectionKey> it = selectionKeys.iterator();
                SelectionKey key = null;
                while ( it.hasNext()) {
                    key = it.next();
                    it.remove();

                    try {
                        handleInput(key);
                    } catch (Exception e){
                        if ( key != null) {
                            key.cancel();
                            if ( key.channel() != null) {
                                key.channel().close();
                            }
                        }
                    }
                }
            } catch (Throwable t) {
                t.printStackTrace();
            }
        }

        if ( selector != null ) {
            try {
                selector.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }


    private void handleInput(SelectionKey key ) throws IOException {

        if ( key.isValid()) {
            if ( key.isAcceptable()) {
                ServerSocketChannel ssc = (ServerSocketChannel)key.channel();
                SocketChannel sc = ssc.accept();
                sc.configureBlocking(false);

                sc.register(selector, SelectionKey.OP_READ);
            }

            if ( key.isReadable()) {
                SocketChannel sc = (SocketChannel)key.channel();
                ByteBuffer readBuffer = ByteBuffer.allocate(1024);
                int readBytes = sc.read(readBuffer);
                if ( readBytes > 0 ) {
                    readBuffer.flip();
                    byte[] bytes = new byte[readBuffer.remaining()];
                    readBuffer.get(bytes);
                    String body = new String(bytes, "UTF-8");

                    System.out.println("The time server receive order: " + body);
                    String currentTime =  "QUERY TIME ORDER".equals(body) ? LocalDateTime.now().toString() : "BAD ORDER";
                    doWrite(sc, currentTime);
                } else if ( readBytes < 0 ) {
                    //对端链路关闭
                    key.cancel();
                    sc.close();
                } else {
                    //读到0字节，忽略
                }

            }


        }

    }

    private void doWrite(SocketChannel channel, String response) throws IOException {
        if ( response != null && response.trim().length() > 0) {
            byte[] bytes = response.getBytes();
            ByteBuffer writeBuffer = ByteBuffer.allocate(bytes.length);
            writeBuffer.put(bytes);
            writeBuffer.flip();
            channel.write(writeBuffer);
        }
    }


}
